Referring to FIG. 1, a conventional incandescent light bulb 5 includes base 10, and evacuated envelope or diffuser cover 14 (hereinafter “diffuser cover”). Diffuser cover 14, which is typically pear-shaped, surrounds a filament (not shown) that is electrically connected to base 10 for electrical connection to a conventional lamp socket. A well known base is an Edison screwbase, as shown, which is electrically connectable to an Edison screw socket.
In recent years, compact fluorescent lamp packages have been introduced into the market. These lamp packages are particularly desirable because of their energy efficiency.
Referring to FIG. 2A, a prior art compact fluorescent lamp package (CFLP) 7 consists of fluorescent lamp 12, lamp holder 13, auxiliary housing 15 for housing ballast 17 and interfacing between lamp holder 13 and base 10. In most CFLPs an Edison screwbase is used for a reliable mechanical and electrical connection to a standard Edison socket, although the sockets are known and used.
The typical height of a standard incandescent light bulb is about 4.5 in. A conventional CFLP due to its auxiliary elements such as auxiliary housing 15 is taller than a conventional incandescent light bulb 5. As a result, a conventional CFLP may extend out of a lamp shade or fixture adapted for an incandescent light bulb causing an undesirable appearance, or may not fit within an existing fixture.
Also, because ballast 17 is housed in auxiliary housing 15, the heat generated by ballast 17 cannot escape very efficiently. Referring, for example, to FIG. 2B, in a typical enclosure or downlight fixture 19, the heat generated from the lamp and ballast of a conventional CFLP 7 collects up in the fixture around the CFLP 7 without any path to escape.
As a result, there is a higher ambient temperature around CFLP 7 which causes the internal components of the CFLP 7, especially ballast 17, to run at even higher temperatures, e.g. above 150° C. The increase in the internal heat decreases reliability, causes field failures and limits the use of a conventional CFLP to open rather than enclosed fixtures all of which discourage the acceptance of CFLPs in the marketplace. In addition, the physical dimensions and the unusual appearance of conventional CFLPs are believed to adversely affect their desirability.